Sorted By Test Name - Mayo Medical Laboratories

FCBG
90148
FCORT
91644
CRANU
82920
identification of patients with 11 beta-hydroxylase deficiency among a large group with alleged
21-hydroxylase deficiency. J Clin Endocrinol Metab 2006;91:2179-2184
Cortisol Binding Globulin (Transcortin)
Reference Values:
Adult: 19-45 mg/L
Pediatric
Preterm Infants:
< 8 days: 6-26 mg/L
Pediatric data from pediatric research, 1994, 37:112-116
TEST PERFORMED BY QUEST DIAGNOSTICS, NICHOLS INSTITUTE
33608 ORTEGA HWY
SAN JUAN CAPISTRANO, CA 92690-6130
Cortisol, Free
Reference Values:
Adult Reference Ranges for Cortisol, Free, LC/MS/MS:
8:00-10:00 AM 0.07-0.93 mcg/dL
4:00-6:00 PM 0.04-0.45 mcg/dL
10:00-11:00 PM 0.04-0.35 mcg/dL
Test Performed by: Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano, CA 92690-6130
Cortisol, Free, Random, Urine
Clinical Information: Cortisol is a steroid hormone synthesized from cholesterol by a multienzyme
cascade in the adrenal glands. It is the main glucocorticoid in humans and acts as a gene transcription
factor influencing a multitude of cellular responses in virtually all tissues. Cortisol plays a critical role in
glucose metabolism, maintenance of vascular tone, immune response regulation, and in the body's
response to stress. Its production is under hypothalamic-pituitary feedback control. Only a small
percentage of circulating cortisol is biologically active (free), with the majority of cortisol inactive
(protein bound). As plasma cortisol values increase, free cortisol (ie, unconjugated cortisol or
hydrocortisone) increases and is filtered through the glomerulus. Urinary free cortisol (UFC) correlates
well with the concentration of plasma free cortisol. UFC represents excretion of the circulating,
biologically active, free cortisol that is responsible for the signs and symptoms of hypercortisolism. UFC
is a sensitive test for the various types of adrenocortical dysfunction, particularly hypercortisolism
(Cushing syndrome). A measurement of 24-hour UFC excretion, by liquid chromatography-tandom mass
spectrometry (LC-MS/MS), is the preferred screening test for Cushing syndrome. LC-MS/MS
methodology eliminates analytical interferences including carbamazepine (Tegretol) and synthetic
corticosteroids, which can affect immunoassay-based cortisol results.
Useful For: Investigating suspected hypercortisolism when a 24-hour collection is prohibitive (ie,
pediatric patients)
Interpretation: Most patients with Cushing syndrome have increased 24-hour urinary excretion of
cortisol. Further studies, including suppression or stimulation tests, measurement of serum corticotropin
(adrenocorticotropic hormone) concentrations, and imaging are usually necessary to confirm the diagnosis
and determine the etiology. Values in the normal range may occur in patients with mild Cushing
syndrome or with periodic hormonogenesis. In these cases, continuing follow-up and repeat testing are
necessary to confirm the diagnosis. Patients with Cushing syndrome due to intake of synthetic
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